Sensing and slow light applications based on graphene metasurface in terahertz

A simple structure graphene metasurface composed of a continuous graphene strip and a truncated graphene strip is designed and investigated for sensing and slow light applications in terahertz. The results reveal that plasmonic-induced transparency (PIT) can be produced in our designed graphene metasurface with the destructive interference between bright and dark modes. Transmission, reflectivity, and absorbance spectra of optical response effectively tuned by the Fermi level, and numerical results are consistent with theoretical results of developed coupled mode theory (CMT). In addition, PIT window is also tuned by the polarization angle of the linearly polarized plane light. Intriguingly, owing to the surface plasmon has field enhancement and strong dispersion, our proposed graphene metasurface exhibit potential optical applications, such as the sensing and the slow light. The sensitivity and Figure of merit (FOM) for sensing characteristics reach up to 0.7928 THz/RIU and 8.12, respectively. The largest group index is of 511 for slow light effect. Therefore, our proposed graphene-based metasurface may be expected to make an important contribution in micro-nano optical sensing and slow light devices.